<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
        }
        ul li{
            list-style: none;
        }
        .flex{
            width: 500px;
            height: 500px;
            display: flex;
            border: 1px solid #000
        }
       .wrap{
           /* 成列排放 */
           /* flex-direction: column; */

            /* 弹性盒子的子元素超出父元素的时候是否换行 */
           /* flex-wrap: nowrap;  */
           /* flex-wrap: wrap;  */
            
           /*  倒转排列*/
           /* flex-wrap: wrap-reverse; */

           /* flex-flow: column-reverse; */

           /* y轴对齐方式 */
           /* align-items: baseline; */
           /* align-items: center; */
           /* align-items: flex-end; */

           /* 设置行对齐，某一行的对齐方式 */
           /* align-content: center; */

           
       }

        .content{
            width: 100px;
            height: 40px;
            background-color: green;
        }
    </style>
</head>
<body>
    <ul class="wrap flex">
        <li class="content">123</li>
        <li class="content" style="height: 80px;">123</li>
        <li class="content">123</li>
        <li class="content">123</li>
        

    </ul>
</body>
</html>